But what do we do if a UFO really comes invading us?

After all I've done to drive 'em off.

How can you be so sure that it'll be an invasion? There can be other explanations, you know.

For example?

The ones on the UFO are actually Earthlings.

The life on Earth has repeated the process of prospering and demising many times, but a certain race with superior scientific technology have put in efforts into outer space development...